Drill bit



W. G. GREEN DRILL BIT Dec. 25, 1951 2 SHEETS-SHEET 1 Filed Sept. 26, 1947 3 wu c/wfo'o William f drew Dec. 25, 195] w GREEN 2,579,819

DRILL BIT 2 SHEETSSHEET 2 Filed Sept. 26, 1947 Patented Dec. 25, 1951 DRILL BIT William G. Green, Dallas, Tcx., assignor to Engineering Laboratories, Incorporated, Tulsa, Okla, a corporation of Oklahoma Application September 26, 1947, Serial No. 776,313

This invention relates to drill bits and more particularly to deep well bits of the type which include a plurality of rotatable cone cutters mounted on the bit head.

In the art of deep well drilling it is customary to rotate in the bore hole a hollow drill bit having a head portion provided with forks in each of which is mounted a spindle for supporting, for free rotation, a cutter cone having serrated faces for cutting or abrading the ground or rock in which the well is being drilled. Mud is supplied centrally to the drill bit and is discharged over the cutters to wash away the cuttings and to lubricate the exterior of the cutters,

In view of the great weight which is transmitted to the cutters through their respective spindles, a bearing problem of considerable magnitude is presented. In attempts to solve this problem resort has been had to various bearing arrangements. It is rather easy to calculate the lines of action of the forces which act on the cutter cones and their supporting spindles and, consequently, it is not unusually difficult to determine the preferred location of the bearings which are required. However, due to the fact that the cutter cone must present a continuous, unitary, uninterrupted outer surface so that iii-leakage to the bearing area is wholly prevented and the cutter cone is afforded adequate mechanical strength, many difiiculties are presented in assembling the bearings used in mounting the cutter cone. Thus, when the calculations indicate that a bearing should be located in some specific 12 Claims. (Cl. 3088.2)

position, it has been found virtually impossible, as

a constructional matter, to put the bearing in that position and, at the same time, to meet practical criteria regarding cost and ease of assembly and repair.

Accordingly, it is an object of the present invention to provide a cutter cone assembly having bearings which are located in the preferred position to withstand heavy shock, which are characterized by long wearing qualities and which are also susceptible of easy and convenient assembly and disassembly for repairs, cleaning or lubrication.

Other objects and advantages of the invention will be apparent upon consideration of the following detailed description of several embodiments thereof in conjunction with the annexed drawings wherein:

Figure 1 is an elevational view of a deep well drill bit constructed in accordance with the principles of the present invention, two of the normally used three cutter cones being removed for convenience of illustration;

Figure 2 is a vertical sectional view taken along the line 22 of Figure l;

Figure 3 is a detailed perspective view of a thrust ring used in the assembly of the cutter cone shown in Figures 1 and 2;

Figure 4 is a view in section taken along the line 4-4 of Figure 2;

Figure 5 is a detailed perspective view of a bearing positioning and guiding sleeve used in the assembly of the cutter cone shown in Figures 1-4 inclusive;

' Figure 6 is a sectional view similar to Figure 4 illustrating a modified arrangement of bearings between the cutter cone and its spindle; and

Figure '7 is a view similar to Figure 6 illustrating a still further modification of the bearing interposed between the cutter cone and its supporting spindle.

Now referring in greater detail to Figures 1-5 inclusive, the reference numeral Ill designates a bit head having a tapered threaded shank portion II adapted for attachment to the mud pipe of a drill rig and three forks l2, l3 and [4. The forks are provided respectively with tines [2a and b, l 3a and b and Ma and b defining between them a space for the reception of the shank of a spindle [5 which supports a cutter cone [6 as shown in Figure 2. The bit head I0 is hollow and is provided with a mud channel IT, a manifold 18 and three mud discharge conduits (two of which are shown at I!) and 20) for serving respectively the several cutter cones to be mounted on the drill head.

The cutter cone assembly illustrated particularly in Figures 2 and 4 is comprised essentially of the supporting spindle l5 and the cutter cone I6. The spindle I5 is provided with a frusto conical bearing surface 2| at one end thereof, and a threaded cylindrical portion 22 at the other end thereof, Between the portions 2! and 22 there are provided cylindrical surfaces at 23 and at 24, the surface at 23 having a slightly greater diameter than that at 24, so as to define a radial shoulder 25 between the two surfaces. The inner surface of the cone l6 generally corresponds in a complementary sense to the surfaces of the spindle I5. It will be noted however, that an annular groove 25 is provided in the cutter IS in a plane normal to the axis of rotation and lying just about between the bearing surfaces 23 and 24 of the spindle Hi after the spindle and cutter cone have been assembled.

Further description of the cutter cone assembly as shown in Figure 4can best be effected by describing the manner in which the assembly is made. First the spindle I5 is inserted in the hollow interior of the cutter cone [5 until the frusto conical end surface 2| is substantially in. registry with the complementary inner surface of the cutter cone l5. At this stage, an annularspace is defined between the bearing surface- 23 of the spindle l5 and a complementary bear-; ing surface 27 of the interior of the cutter cone l6. Into this bearing space is inserted a cage 28 supporting circumferentially spaced rollers. 29 so as to provide roller bearings covering substantially the entire bearing area between the bearing surfaces 23 and 21. assembly 28 and the rollers 29 have been inserted, a split annular ring 36 of the type shown in Figure 3 is circumferentially compressed and inserted in the groove at 26 between thebearing surface 21 from another bearing surface 3|.

Upon reference to Figure 3 it will be noted that the ring'Bil is radially slotted at 32 to permitreduction of its circumference durin the installation within the cutter cone it. After the ring 39 has been positioned, a sleeve 33, which is. shown in Figure 5, is fitted axially over the bearing surface 24 of the spindle [5. The sleeve 33 is provided with a main upper bearing surface 34 and with an annular flange at one end, which is indicated at 35 in the drawings. Flange 35 is pressed up against the shoulder at so that the outer surface of the flange registers with the ring and serves to hold it in expandedposition. within the groove 26. In order that the sleeve. will notrotate. during the rotation of: the cone; cutter I 6, a projecting tongue 36 is provided which fits between the tines I2a and 12b of the fork IQ of the bit head 10. There is now provided between the bearing space, or surface, 3| on the interior of the cutter cone [5 and the outer bearing surface 34 of the sleeve 33, anannular zone of considerable axial length. Into this zone there is inserted a roller bearing cage 31: provided with a plurality of roller bearings 38. After the insertion of this second roller bearing assembly another ring, bearing reference character 35, is inserted in a groove at 40 provided near the mouth of the cavitywithin the cutter cone It. In the bottom of the groove 4fl is located a communicating but smaller groove 4| which is provided with packing material at 42 to prevent the out-leakage oflubricating material from the bearing area. At this pointitcan be seen that the singlecutter cone is substantially completely assembled. If now,

the threaded end 22 of the spindle be passed throughthe tines of the fork [2, all that is necessary to attach the cutter cone assembly to the bit head is the application of a nut which is shown inFigure 4 at 43, and a spot weld to insure the maintenance of. the connection during use.

From the foregoing description it will be apparent that by the choice of bearing sockets and spacer rings which applicant has made, it is pos- After the bearing corresponds generally in structure and function to the spindle [5. The configuration of the inner cavity of the cutter cone 44 is similar to that V their supporting cage 28, a ball-bearing raceway =45 is used. A compressible annular ring 4! separates the hall-bearing raceway 46 from another raceway 48 which corresponds in position and function to the roller-bearing assembly 38 shown in Figure 4. The steps in assembling the appa- :ratus shown in Figure 6 correspond in sequence and in form to those described above in connection with Figure 4. The ball races of the bearings 46 and 41 are so arranged that both the axial and the radial thrust of the cutter cone 44 'is absorbed thereby. The attachment of the Supporting spindle 45 to the fork of the bit. head is effected by the use of a nut 49 in a manner similar to that described above.

Now referring to Fig. 7, there is shown a cutter cone 50 mounted for free rotation on a spindle 5E. The cutter cone is provided with a bearing surf-ace at 52 and a threaded surface at 53. The spindle 5| is provided with a bearing surface at 54 lying in radial registry with bearing surface 52 of the cone and with a surface at 55 adapted to receive thereover a sleeve 55 similar to the sleeve 33 shown in Figure. 5 but having a radially larger flange 58. The structure and operation of the assembly shown in Figure 7 will be apparent from a description of the mode of its assembly. A roller-bearing cage 51 is inserted in the annular space defined between the bearing surfaces 52 and 54. Thereafter the sleeve 55 is inserted over the spindle 5| until its flange 58 assumes the position shown in the drawing against the shoulder 59 between the surfaces 52 and 53 of the cone. Thereafter an elongate annular member 80 having its outer cylindrical surface threaded, is screwed into the end of the cutter cone 50 so that its inner surface defines with the outer surface of the sleeve 53 an annular bearing space. A set of roller bearings 6| are located in this space. The an-. nular member 69 is provided with a groove at 62 having packings 63 therein to inhibit the migration of lubrication material from'the bearing area. Underlying the packing material 62, and overlying the outer surface of the sleeve 56, there is interposed a solid ring 64. The attachment of the spindle 5| to the tines of the fork depending from the bit head is effected in the manner described above.

An additional feature of the assembly of Figure '7 which does not appear in the assemblies shown in Figures 1-6 inclusive, is the provision of a central bore through the spindle 5! opening into the bearing space between the spindle and the cutter cone 50. This bore is indicated in Figure 7 by the reference numeral 65 and at one end of the bore there is provided a lubrication fitting- 56 through which a lubricant, may be delivered to the bore for subsequent delivery to the bearing area between the cuttercone and the spindle.

In describing this; invention reference has beenmade to but several embodiments thereof; and it is apparent that various modifications may be made within the scope of the appended claims. It is to be noted that the common feature of the e e a rms f he nventipn. w i h. ave. been described above is the provision of axially aligned sets of bearings with intermediate means for counteracting axial movement, the assembly of the intermediate means serving to position the set of bearings nearest to the fork of thebit. No description has been given of the exterior construction of the several cutter cones shown, it being understood that teeth are provided on these cones for the purpose of cutting in the area to be drilled, the provision of such teeth being entirely conventional and forming no part of the present invention.

What is claimed is:

1. In a cutter cone assembly for drill bits which includes a spindle element and a cutter cone element mounted for rotation thereover, the improvement that comprises axially spaced sets of antrifriction bearings between the cutter cone and spindle, said sets having substantially equal inner and outer diameters, means extending outwardly beyond the said outer diameters of said sets and in engagement with said cone for holding said sets against axial displacement, said means acting through said bearings to restrain said cone also against axial movement, and annular means holding said set-holding means in set-holding position.

2. In a cutter cone assembly for drill bits which includes a spindle element and a cutter cone element mounted for rotation thereover, the improvement that comprises axially spaced sets of antriiriction bearings between the cutter cone and spindle, said sets having substantially equal inner and outer diameters, said cutter cone having an annular groove therein opening into the space between said sets of bearings, circumferentially adjustable ring means situated in said groove and serving to hold said sets of bearings against axial displacement, said means acting through said bearings to restrain said cone also against axial movement, and annular means for holding said ring means in circumferentially expanded position, a portion of said annular means lying between the spindle element and one of the sets of bearings.

3. In a cutter cone assembly for drill bits which includes a spindle element and a cutter cone element mounted for rotation thereover, the improvement that comprises axially spaced sets of antrifriction bearings between the cutter cone and spindle, said sets having substantially equal inner and outer diameters, said cutter cone ha" ing an annular groove therein opening into the space between said sets of bearings, a circumferentially adjustable compressible ring situated in said groove and serving to hold said sets of bearings against axial displacement, said means acting through said bearings to restrain said cone also against axial movement, and a flanged sleeve surrounding the spindle with the flange urging the ring to circumierentially extended position and the outer surface of the sleeve engaging one of the sets of bearings.

4. A cutter cone assembly as claimed in claim 3 in which the sleeve is provided with an axially extending portion-adapted to interlock with the tines of the fork of a drill bit to hold the sleeve on the spindle against rotation.

5. In a cutter cone assembly for drill bits which includes a spindle element and a cutter cone element mounted for rotation thereover, the improvement that comprises an inner set of antifriction bearings and an outer set of antifriction bearings axially spaced and lying between the cutter cone and spindle, said sets having substantially equal inner and outer diameters, said outter cone having an annular groove therein opening into the space between said sets of bearings, a circumferentially adjustable compressible ring situated in said groove and extending between the sets of bearings to hold them against axial displacement, a flanged sleeve surrounding the spindle with the flange urging the ring to circumferentially extended position and the outer surface of the sleeve engaging the outer set of bearings, and a second ring surrounding said sleeve and bearing against the outer end of the outer set of bearings.

6. A cutter cone assembly as claimed in claim 1 in which the antifriction bearings are roller bearings.

7. A cutter cone assembly as claimed in claim 1 in which the antifriction bearings are ball bearmgs.

8. In a cutter cone assembly for drill bits which includes a spindle element and a cutter cone element mounted for rotation thereover, the improvement that comprises axially spaced sets of antifriction bearings between the cutter cone and spindle, said sets having substantially equal inner and outer diameters, a flanged sleeve surrounding said spindle, the flange extending radially outwardly between the sets of bearings, and a sleeve threaded to the cone, coaxial with the flanged sleeve and in axial bearing engagement with its flange, one of the sets of bearings being located between said sleeves.

9. In a cutter cone assembly for drill bits which includes a spindle element and a cutter cone element mounted for rotation thereover, the improvement that comprises an inner set of antifriction bearings and an outer set of antifriction bearings axially spaced and lying between the cutter cone and spindle, said sets having substantially equal inner and outer diameters, a flanged sleeve surrounding said spindle, the flange extending radially outwardly between the sets of bearings, a sleeve threaded to the cone and coaxial with the flanged sleeve and in axial bearing engagement with its flange, the outer set of bearings being located between said sleeves, and a ring surrounding the end of said flanged sleeve remote from the flange, said ring enclosing the annular space at the outer end of the outer set of bearings.

10. A cutter cone assembly as claimed in claim 1 in which the spindle is provided with an axial channel for the distribution of lubricant to the space between the spindle and the cutter cone.

11. A cutter cone assembly as claimed in claim 5 in which the cutter surface of the second ring bears against a portion of the inner surface of the cone and a sealing gasket is provided therebetween.

12. A cutter cone assembly as claimed in claim 9 in which a sealing gasket is provided between the outer surface of the ring and the inner surface of the threaded sleeve.

WILLIAM G. GREEN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 604,003 Childs May 10, 1898 1,289,827 Laycock Dec. 31, 1918 2,351,357 Miller June 13, 1944 2,368,175 Thomas Jan. 30; 1945 

